Apparatus and method for drying semiconductor substrates

ABSTRACT

A drying apparatus and method of drying a wafer including supplying a drying material for drying a wafer and controlling a flow of the drying material to uniformly or substantially uniformly dry the wafer. The flow of the drying material may be controlled by a vent unit including at least one part for controlling the flow of the drying material to uniformly or substantially uniformly dry the wafer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of, and claims priority under 35 U.S.C. § 120 to, co-pending application Ser. No. 10/831,175 filed on Apr. 26, 2004, which claims the benefit under 35 U.S.C. § 119(a) of Korean Patent Application No. 2003-0077781, filed on Nov. 4, 2003. The contents of both of these applications are hereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus and method for drying semiconductor substrates, and more particularly to an apparatus and method for drying semiconductor substrates using a vent unit.

2. Description of the Related Art

Clean semiconductor substrates are useful for improving the efficiency and correct operation of a semiconductor device. Unclean semiconductor substrates can lead to problems. These problems may include inefficiency and/or incorrect function of the fabricated semiconductor.

A conventional method of cleaning semiconductor substrates involves a wet cleaning process wherein a chemical solution is used to remove impurities in the semiconductor substrate. After the wet cleaning process, it may be necessary to remove any remaining chemical solution used in the wet cleaning process from the semiconductor substrate.

A conventional method of removing a chemical solution from a semiconductor substrate following a wet cleaning process involves the passage of the semiconductor substrate through two distinct stages, a rinsing stage and a drying stage. A conventional rinse/dry apparatus, shown in FIG. 1, may include a rinsing chamber 101, a drying chamber 103, a gas supplier 105, including a gas inlet conduit 105 a, and a vent 107.

During the rinsing stage, de-ionized water 109 may be supplied to the rinsing chamber 101, as shown in FIG. 1. The semiconductor wafer 111 containing the remains of the chemical solution is dipped in the de-ionized water 109. The remains of the chemical solution are removed in the rinsing chamber 101, and the de-ionized water 109 is absorbed on the surface of the rinsed semiconductor wafer 111.

Following the above described rinsing stage, a drying stage is initiated. During the drying stage, the rinsed semiconductor wafer 111 is raised from the rinsing chamber 101 to the drying chamber 103. Concurrently, a gas 115, which may be isopropyl alcohol (IPA), is injected in the interior of the drying chamber 103 from the gas supplier 105. The gas 115 injected into the drying chamber 103 is directed towards the semiconductor wafer 111. After passing over the semiconductor wafer 111, the gas 115 is exhausted through the vent 107 out of the drying chamber 103. When the semiconductor wafer 111 is sufficiently dry, the drying stage is over and the process of removing the chemical solution left on the semiconductor wafer 111 during the wet cleaning process is complete.

With conventional methods and apparatuses, water marks 113 a and 133 b, may remain on the semiconductor wafer 111 following the drying stage, as shown in FIG. 2. One reason water marks 113 a and 133 b may occur is due to uneven flow of the gas 115 during the drying stage when the gas 115 is injected into the drying chamber 103 and directed towards the semiconductor wafer 111. These water marks 113 a and 133 b may be formed into at least two distinct locations. The first water marks 113 a may be formed on both sides of the upper portion of the semiconductor wafer 111 in the opposite direction of a plat zone 111 a. The water marks 113 b may be formed adjacent to the plat zone 111 a.

Water marks, as described above, may cause problems in the semiconductor fabrication process, such as reducing the yield rate of the semiconductor devices produced.

SUMMARY OF THE INVENTION

Exemplary embodiments of the present invention are directed to a drying apparatus including a drying chamber for supplying a drying material for drying a wafer and a vent unit for controlling a flow of the drying material to uniformly or substantially uniformly dry the wafer.

Exemplary embodiments of the present invention are directed to a vent unit including at least one part for controlling a flow of a drying material to uniformly or substantially uniformly dry the wafer.

Exemplary embodiments of the present invention are directed to a method of drying a wafer including supplying a drying material for drying the wafer and controlling a flow of the drying material to uniformly or substantially uniformly dry the wafer.

In exemplary embodiments of the present invention, the apparatus for drying and rinsing the semiconductor substrate may include a rinsing chamber, a drying chamber, and/or a vent unit. In exemplary embodiments of the present invention, the rinsing chamber may provide sufficient space for a rinsing process as well as a wet cleaning process. In exemplary embodiments of the present invention, the rinsing chamber may comprise two or more horizontal vent slits penetrating an upper portion on opposite sides of the rinsing chamber. In an exemplary embodiment, the drying apparatus further includes a cleaning chamber containing a cleaning material for cleaning the wafer. The cleaning material is HF.

In exemplary embodiments of the present invention, the drying chamber may be positioned above the rinsing chamber and have an exposed lower portion. The exposed lower portion may allow the rinsed wafers to pass through from the rinsing chamber during a drying stage. The interior of the drying chamber may have sufficient space for the execution of the drying stage.

In exemplary embodiments of the present invention, the drying chamber may include a gas supplier, which supplies a purge gas, including but not limited to nitrogen, for exhausting contaminated air in the drying chamber during a rinse stage or the wet cleaning process. The gas supplier may further supplies a drying gas, including but not limited to IPA, during a drying stage.

In exemplary embodiments of the present invention, the drying chamber may have a first slit and a second slit penetrating through each of its lower sides.

Exemplary embodiments of the present invention may incorporate a vent unit, which may move in a horizontal direction through the first slit and the second slit in the drying chamber. In exemplary embodiments of the present invention, the vent unit may move through the first slit and the second slit, controlling flow between the rinsing chamber and the drying chamber.

In exemplary embodiments of the present invention, the vent unit may include a first door with slits and a second door with slits, which may or may not be identical, designed to move through the first slit and the second slit. The first door may move horizontally through the first slit, and the second door may move horizontally through the second slit. In exemplary embodiments of the present invention, the slits incorporated in the doors may be designed to allow the drying chamber and the rinsing chamber to be partially or fully isolated from each other. In exemplary embodiments of the present invention, the slits incorporated in the doors may control flow between the drying chamber and the rinsing chamber. Various exemplary embodiments may exist with regard to the specific formations of the slits in the first door and the second door.

In exemplary embodiments of the present invention, the flow control enabled by the vent unit may allow for uniform or more uniform distribution of the drying gas applied to the semiconductor wafer during the drying stage. Accordingly, exemplary embodiments of the present invention may reduce or eliminate the above-mentioned watermarks.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will become more fully understood from the detailed description given below and the accompanying drawings, which are given for purposes of illustration only, and thus do not limit the invention.

FIG. 1 illustrates a rinsing chamber and a drying chamber of a conventional apparatus.

FIG. 2 illustrates a plane view of water marks formed on semiconductor substrates using a conventional apparatus.

FIG. 3 illustrates a drying apparatus in accordance with an exemplary embodiment of the present invention.

FIG. 4 a illustrates a vent unit in accordance with an exemplary embodiment of the present invention and FIG. 4 b illustrates a cross-section of the vent unit of FIG. 4 a, along the line I-I.

FIG. 5 a illustrates a vent unit in accordance with another exemplary embodiment of the present invention and FIG. 5 b illustrates a cross-section of the vent unit of FIG. 5 a, along the line II-II.

FIG. 5 c illustrates another cross-sectional view of the vent unit FIG. 5 a.

FIG. 6 a illustrates a vent unit in accordance with another exemplary embodiment of the present invention and FIG. 6 b illustrates a cross-section of the vent unit of FIG. 6 a, along the line III-III.

FIG. 6 c illustrates another cross-sectional view of the vent unit FIG. 6 a.

FIG. 7 illustrates a method, including a rinsing operation, in accordance with another exemplary embodiment of the present invention, incorporating a vent unit.

FIG. 8 illustrates a method, including a drying operation, in accordance with another exemplary embodiment of the present invention, incorporating a vent unit.

It should be noted that these Figures are intended to illustrate the general characteristics of methods and devices of exemplary embodiments of this invention, for the purpose of the description of such exemplary embodiments herein. These drawings are not, however, to scale and may not precisely reflect the characteristics of any given embodiment, and should not be interpreted as defining or limiting the range of values or properties of exemplary embodiments within the scope of this invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE PRESENT INVENTION

A drying apparatus in accordance with an exemplary embodiment of the present invention includes a first chamber 1 and second chamber 3, as shown in FIG. 3. The first chamber 1 may provide space for a rinsing process or a cleaning process to be performed prior to a semiconductor substrate entering the drying apparatus shown in FIG. 3.

The first chamber 1 may include an opened upper portion and a first vent slit 1S′ and a second vent slit 1S″ through an upper portion of both sides thereof. It is noted that although FIG. 3 illustrates one first vent slit 1S′ and one second vent slit 1S″, any number of either vent slits could also be used, as would be evident to one of ordinary skill in the art.

The second chamber 3 may include an opened lower portion allowing semiconductor wafers (for example, rinsed semiconductor wafers) to pass therethrough from the first chamber 1 to the interior of the second chamber 3. The opened lower portion of the second chamber 3 may include space for a robot arm or other wafer moving mechanism, to assist in the drying of semiconductor wafers.

The second chamber 3 may include a gas supplier 7, which supplies a purge gas for exhausting any contaminated gas (for example, contaminated air) from the second chamber 3 during the rinse process or the cleaning process and may provide a drying gas during drying process in the second chamber 3.

The second chamber 3 may further include 3 a first slit S1 and a second slit S2 through each of the lower part of both sides thereof. It is noted that although FIG. 3 illustrates one slit S1 and one slit S2, any number of either vent slits could also be used, as would be evident to one of ordinary skill in the art.

A vent unit 5 is movable in a horizontal or substantially horizontal direction through the slits S1,S2 thereby separating or connecting (depending on the position of the vent unit 5) the interior spaces of the first and second chambers 1, 3. The vent unit 5 may include a first slit door type exhausting unit 5 a horizontally or substantially horizontally moving through the first slit S1 and a second slit door type exhausting unit 5 b horizontally or substantially horizontally moving through the second slit S2. The second chamber 3 may be sealed when the first and second slit door type exhausting units 5 a, 5 b contact each other in the second chamber 3. In this case, the air in the second chamber 3 can be exhausted through a plurality of the vent holes formed in the first and second slit door type exhausting units 5 a, 5 b.

FIGS. 4 a and 4 b illustrate a vent unit 5 in accordance with an exemplary embodiment of the present invention. The vent unit 5 may include a first slit door type exhausting unit 5 a and a second slit door type exhausting unit 5 b. The first slit door type exhausting unit 5 a may include a first body 11′ and first exhausting conduit 11 e′. The first body 11′ may have a first lower panel 11 g′, a first inner space 11 s′, a first upper panel 11 t′, and a first wall having a first inner sidewall 11 d′, a first outer sidewall 11 w′, a first front wall 11 f′ and a first rear wall 11 r′.

The first upper panel 11 t′ may have first vent holes including first, second and third groups of vent holes 11 a′, 11 b′, 11 c′. It is noted that although FIGS. 4 a and 4 b illustrate three groups of vent holes, any number of vent hole groups (or vent holes) could also be used, as would be evident to one of ordinary skill in the art.

The first body 11′ may be divided into a first center region R1′, a first edge region R3′, and a first intermediate region R2′. It is noted that although FIGS. 4 a and 4 b illustrate one center region R1′, one edge region R3′, and one intermediate region R2′, any number of center regions R1′, edge region R3′, and/or intermediate regions R2′ could also be used, as would be evident to one of ordinary skill in the art.

The first group of vent holes 11 a′ may have a first width W1, the second group of vent holes 11 b′ may have a second width W2, and the third group of vent holes 11 c′ may have a third width W3. The first, second and third groups of vent holes may all have the same length L. If the first width W1 is larger than the second and third widths W2, W3, and the second width W2 is equal to the third width W3, the first group of vent holes 11 a′ may be arranged with the same density (hole number) as the second group of vent holes 11 b′, and the third group of vent holes 11 c′ may be arranged with a lower density (hole number) than the second group of vent holes 11 b′.

Alternatively, the first width W1 may be larger than the second width W2, and the second width W2 may be larger than the third width W3. In this case, the first, second and third groups of vent holes 11 a′, 11 b′, 11 c′ all may be arranged with the same density. Also, the first, second and third widths W1, W2, W3 may all be equal to each other. In this case, the first group of vent holes 11 a′ may be arranged at a higher density than the second group of vent holes 11 b′ and the third group of vent holes 11 c′ may be arranged at a lower density than the second group of vent holes 11 b′. It is noted that other vent hole widths, lengths, densities, and/or combinations thereof could also be used, as would be evident to one of ordinary skill in the art.

The first, second and third groups of vent holes 11 a′, 11 b′, 11 c′ may also have various shapes, for example, a square, a circle, a rectangular, or other geometric shape. Also, the first body 11′ may be divided into other regions than center, intermediate and edge regions R1, R2, R3.

The second slit door type exhausting unit 5 b may be the same as or different from the first slit door type exhausting unit 5 a. The second slit door type exhausting unit 5 b may include elements 11″, 11 a″, 11 b″, 11 c″, 11 d″, 11 e″, 11 f′, 11 g″, 11 r″, 11 s″, 11 t″, 11 w″, R1″, R2″, and R3″ corresponding to elements 11′, 11 a′, 11 b′, 11 c′, 11 d′, 11 e′, 11 f, 11 g′, 11 r′, 11 s′, 11 t′, 11 w′, R1′, R2′, and R3, of the first slit door type exhausting unit 5 a.

FIGS. 5 a-5 c illustrate a vent unit 5 in accordance with another exemplary embodiment of the present invention. The vent unit 5 may be a variable slit door type exhausting unit and may include a first slit door type exhausting unit 31 a and second slit door type exhausting unit 31 b inserted in the first slit door type exhausting unit 31 a. The first and second slit door type exhausting units 31 a, 31 b may have a similar shape to the first and second slit door type exhausting units 5 a, 5 b for example, the first slit door type exhausting unit 31 a may include a first body 33′ and a first exhausting conduit 33 e′.

The first body 33′ may have a first upper panel 33 t′, a first lower panel 33 g′, a first front sidewall 33 f, a first rear sidewall 33 r′, and a first outer sidewall 33 w′. The first upper panel 33 t′ may have first, second and third groups of vent holes 33 a′, 33 b′, 33 c′ passing therethrough. The first body 33′ may have a first opening portion 33 h′ opposite to the first outer sidewall 33 w′.

The second slit door type exhausting unit 31 b may be the same as or different from the first slit door type exhausting unit 31 a. The second slit door type exhausting unit 31 b may include elements 33″, 33 a″, 33 b″, 33 c″, 33 e″, 33 f′, 33 g″, 33 r′, 33 t″, 33 w″, R1″, R2″, and R3″ corresponding to elements 33′, 33 a′, 33 b′, 33 c′, 33 e′, 33 f, 33 g′, 33 r′, 33 t′, 33 w′, R1′, R2′, and R3, of the first slit door type exhausting unit 31 a.

The second opening portion 33 h″ may be smaller than the first opening portion 33 h′. The second chamber 3 may be sealed by contacting the first and second slit door type exhausting units 31 a, 31 b by inserted them in slits S1, S2, respectively, of the second chamber 3. That is, the second opening portion 33 h″ can be inserted in the first opening portion 33 h′ (or vice versa) as will be discussed below in conjunction with FIGS. 5 b and 5 c.

A portion of the vent holes 33 a′, 33 b′, 33 c′ of the first body 33′ may be overlapped with a portion of the vent holes 33 a″, 33 b″, 33 c″ of the second body 33″ by increasing the overlap between the first and second slit door type exhausting units 31 a, 31 b. For example, the first group of vent holes 33 a′ of the first body 33′ can overlap with the first group of vent holes 33 a″ of the second body 33″. In this case, a density of the vent holes arranged covering both the first and second slit door type exhausting units 31 a, 31 b may be decreased and a width of the variable slit door type exhausting unit including the first and second slit door type exhausting units 31 a, 31 b may also be decreased. As a result, the variable slit door type exhausting unit may be suitable for drying wafers having various (for example, smaller) diameters.

It is noted that the variations and/or combinations discussed above with respect to FIGS. 4 a and 4 b are also applicable to FIGS. 5 a-5 c, as would be evident to one of ordinary skill in the art.

FIGS. 6 a-6 c illustrate a vent unit 5 in accordance with another exemplary embodiment of the present invention. The vent unit 5 may include first and second slit door type exhausting units 41 a, 41 b. The first and second slit door type exhausting units 41 a, 41 b may have a shape similar to the first and second slit door type exhausting units 5 a, 5 b or 31 a, 31 b. That is, the first slit door type exhausting unit 41 a may have a first body 43′ and a first exhausting conduit 43 e′. Similarly, the second slit door type exhausting unit 41 b may have a second body 43″ and a second exhausting conduit 43 e″.

The second slit door type exhausting unit 41 b may be the same as or different from the first slit door type exhausting unit 41 a. The second slit door type exhausting unit 41 b may include elements 43″, 43 a″, 43 b″, 43 c″, 43 d″, 43 e″, 43 f′, 43 g″, 43 r″, 43 t″, 43 w″, R1″, R2″, and R3″ corresponding to elements 43′, 43 a′, 43 b′, 43 c′, 43 d′, 43 e′, 43 f, 43 g′, 43 r′, 43 t′, 43 w′, R1′, R2′, and R3, of the first slit door type exhausting unit 31 a.

The first body 43′ may have a first upper panel 43 t′, a first lower panel 43 g′, a first front wall 43 f, a first rear wall 43 r′, a first outer sidewall 43 w′, and a first inner sidewall 43 d′. The second body 43″ may have a second upper panel 43 t″, a second lower panel 43 g″, a second front wall 43 f′, a second rear wall 43 r″, a second outer sidewall 43 w″, and a second inner sidewall 43 d″.

The first and second upper panels 43 t′, 43 t″ may have first and second vent holes respectively passing therethrough. The first upper panel 43 t″ may have first, second and third groups of vent holes 43 a′, 43 b′, 43 c′ passing therethrough. The first vent holes may include first, second and third groups of vent holes 43 a′, 43 b′, 43 c′ passing therethrough. The second upper panel 43 t″ may have first, second and third groups of vent holes 43 a″, 43 b″, 43 c″ passing therethrough. The first, second and third groups of vent holes 43 a′, 43 a″, 43 b′, 43 b″, 43 c′, 43 c″ may all have the same width (W).

A first length L1 of the first group of vent holes 43 a′, 43 a″ may be larger than a second length L2 of the second group of vent holes 43 b′, 43 b″. A third length L3 of the third group of vent holes 43 c′, 43 c″ may be smaller than the second length L2. The first body 43′ may have a first auxiliary panel 45′ to vary an opened area of the vent holes 43 a′, 43 b′, 43 c′ of the first body 43′ by sliding in the horizontal direction along a surface of the first upper panel 43 t′.

The second body 43″ may also have a second auxiliary panel 45″ to vary an opened area of the vent holes 43 a″, 43 b″, 43 c″ of the second body 43″ by sliding in the horizontal direction along a surface of the second upper panel 43 t″.

The first auxiliary panel 45′ may have first, second and third groups of auxiliary vent holes 45 a′, 45 b′, 45 c′, which may have the same size and/or (or neither) the same arrangement as the first, second and third groups of vent holes 43 a′, 43 b′, 43 c′. The second auxiliary panel 45″ may have first, second and third groups of auxiliary vent holes 45 a″, 45 b″, 45 c″ having the same size and/or (or neither) arrangement as the first, second and third groups of vent holes 43 a″, 43 b″, 43 c″. If the first, second and third groups of the auxiliary vent holes 45 a′, 45 a″, 45 b′, 45 b″, 45 c′, 45 c″, respectively are completely overlapped with the first, second and third groups of the vent holes 43 a′, 43 a″, 43 b′, 43 b″, 43 c′, 43 c″, as shown in FIG. 6 a and FIG. 6 b by adjusting the position of first and second auxiliary panel 45′, 45″, the vent holes of the first and second slit door type exhausting units 41 a, 41 b may have the largest open area.

It is noted that the variations and/or combinations discussed above with respect to FIGS. 4 a-4 b and 5 a-5 c are also applicable to FIGS. 6 a-5 c 6, as would be evident to one of ordinary skill in the art.

Referring to FIG. 6 c, after the second chamber 3 shown in FIG. 3 is sealed by contacting the first and second slit door type exhausting units 41 a, 41 b with each other, a size of the opened area of the first, second and third groups of vent holes 43 a′, 43 a″, 43 b′, 43 b″, 43 c′, 43 c″ can be varied by moving the first and second auxiliary panels 45′, 45″ in and out in the horizontal direction.

If the first and second auxiliary panels 45′, 45″ are each moved half the width W toward the first and second inner sidewalls 43 d′, 43 d″, the open area of the all vent holes decreases by half without varying the density of the vent holes. As a result, the exhausting capability of the variable slit door type exhausting unit may be controlled by movement of the first and second auxiliary panels 45′, 45″. The variable slit door type exhausting unit may also be used to vary the pressure in the second chamber 3 after a drying process.

If a drying gas (such as drying gas 27 in FIG. 8) injected into the second chamber 3 has a normal temperature or a temperature lower than the normal temperature of the drying process, the pressure in the second chamber 3 may be lowered reduce or prevent the drying gas from condensing.

Further, if the temperature of the drying gas 27 is low and the pressure of the second chamber 3 is high, a size of the opened area of the vent holes can be made as large as possible by adjusting the first and second auxiliary panels 45′, 45″.

FIG. 7 illustrates a method, including a rinsing operation, in accordance with another exemplary embodiment of the present invention incorporating a vent unit. A rinsing liquid, for example, de-ionized water 21, is supplied into the first chamber 1 and a semiconductor wafer 23 is dipped in the de-ionized water 21 to rinse the wafer 23. The rinsing may include over-flowing the first chamber with the de-ionized water 21.

Humidity in the second chamber 3 may be uniformly or substantially uniformly maintained by injecting a purging gas 25, such as a nitrogen-based gas, into the second chamber 3 and contaminated air in the second chamber 3 may be exhausted. The purging gas 25 may be injected through the gas supplier 7 of the second chamber 3. The gas supplier 7 may include a gas inlet conduit 7 a for supplying the gas, such as the purging gas 25, to the second chamber 3. During the rinsing process, the first and second slit door type exhausting units 5 a, 5 b, (or 31 a, 31 b or 41 a, 41 b) may be positioned in the first and second slits S1, S2 formed in opposite sidewalls of the second chamber 3. The first and second slit door type exhausting units 5 a, 5 b may be arranged to face the first inner sidewall 11 d′ and the second inner sidewall 11 d″, respectively.

During the rinsing process, the first and second slit door type exhausting units 5 a, 5 b can be positioned to achieve a desired (and maybe constant) gap therebetween. In this case, the purging gas 25 injected in the second chamber 3 may be exhausted through the first and second exhausting slits 1 s′, 1 s″ formed in the sidewalls of the second chamber 3 (or the first chamber 1). During the rinsing process, the first and second slit door type exhausting units 5 a, 5 b may be repositioned in a horizontal direction closer to each other or to contact each other. That is, the second chamber 3 may be sealed by contacting the first and second inner sidewalls 11 d′, 11 d″ together. In this case, the purging gas 25 injected into the second chamber 3 may be exhausted through the vent holes 11 a′, 11 a″, 11 b′, 11 b″, 11 c′, 11 c″ of the first and second exhausting units 5 a, 5 b.

During the rinsing process, if the second chamber 3 is sealed by contacting the first and second slit door type exhausting units 5 a, 5 b with each other, the purging gas 25 can not be injected. As shown in FIG. 8, after completing the rinsing process, the rinsed wafer 23 may be raised and moved in the second chamber 3. During the rinsing process, if the second chamber 3 is separated by the first and second slit door type exhausting units 5 a, 5 b, before rising the wafer 23, a moving path for the wafer 23 is formed by separating the first and second slit door type exhausting units 5 a, 5 b from each other. While rinsing the wafer 23, the purging gas 25 can be supplied continuously. After the wafer 23 is rinsed in the second chamber 3, the first and second slit door type exhausting units 5 a, 5 b may be moved in the horizontal direction to thereby contact each other. That is, an opened upper portion of the second chamber 3 may be closed by the first and second slit door type exhausting units 5 a, 5 b. The drying gas 27 may be injected via the gas supplier 27. The drying gas 27 may be a volatile gas capable of substituting the de-ionized water by reaction with each other. For example, the drying gas 27 may be one or more of ethylglycol, 1-propanol, 2-propanol, tetrahydrofurane, 4-hydroxy-4-methyl-2-pentamone, 1-butanol, 2-butanol, methanol, ethanol, isopropyl alcohol, acetone, n-propyl alcohol and dimethylether.

Alternatively, the drying gas 27 may be supplied together with a carrier gas. In this case, the drying gas 27 may be a mixture of the carrier gas and one of ethylglycol, 1-propanol, 2-propanol, tetrahydrofurane, 4-hydroxy-4-methyl-2-pentamone, 1-butanol, 2-butanol, methanol, ethanol, isopropyl alcohol, acetone, n-propyl alcohol and dimethylether. The carrier gas may be nitrogen gas. The carrier gas may have a normal or a higher temperature. If the carrier gas has a temperature higher than a normal temperature, the drying gas 27 may also have a temperature higher than the normal temperature. For example, if the drying gas 27 is a mixture of isopropyl alcohol gas having a normal temperature and nitrogen gas having a temperature higher than the normal temperature, the isopropyl alcohol gas also may have a temperature higher than the normal temperature.

The drying gas 27 may be injected in the second chamber 3 as shown in FIG. 8 may be exhausted through the vent holes 11 a′, 11 a″, 11 b′, 11 b″, 11 c′, 11 c″ of the first and second slit door type exhausting units 5 a, 5 b. The vent holes 11 a′, 11 a″ may be arranged to have the highest number of holes and/or the largest size, in the region adjacent to the inner sidewalls 11 d′, 11 d″. In this arrangement, the drying effect of the drying gas 27 is highest at the first group of the vent holes 11 a′, 11 a′ adjacent the inner sidewalls 11 d′, 11 d″ as shown in FIG. 8. As a result, the drying gas 27 passing through an upper portion of the lower surfaces B of the wafer flows uniformly or substantially uniformly along a direction parallel or substantially parallel to a contour of the edge (in the example of FIG. 8, the rounded edge) of the wafer 23. Accordingly, this can reduce or eliminate water marks formed on the surface of the wafer 23.

It will be apparent to those skilled in the art that other changes and modifications may be made in the above-described exemplary embodiments without departing from the scope of the invention herein, and it is intended that all matter contained in the above description shall be interpreted in an illustrative and not a limiting sense. 

1.-32. (canceled)
 33. A vent unit, comprising: at least one part for controlling a flow of a drying material to uniformly or substantially uniformly dry the wafer.
 34. The vent unit of claim 33, the at least one part including a plurality of vent holes, which determine a flow amount and flow pattern of the drying material through the vent unit.
 35. The vent unit of claim 33, wherein the at least one part controls the flow of the drying material so more drying material flows over a central region of the at least one part than an edge region of the at least one part.
 36. The vent unit of claim 34, wherein more of the plurality of vent holes are located in a central region of the at least one part than an edge region of the at least one part.
 37. The vent unit of claim 34, wherein larger vent holes are located in a central region of the at least one part than an edge region of the at least one part.
 38. The vent unit of claim 34, wherein more of the plurality of vent holes and larger vent holes are located in a central region of the at least one part than an edge region of the at least one part.
 39. The vent unit of claim 34, the vent unit including at least two parts which interact to alter a flow of the drying material through the plurality of vent holes.
 40. The vent unit of claim 34, the vent unit including at least two parts and at least two auxiliary parts which interact to alter flow of the drying material through the plurality of vent holes.
 41. A method of drying a wafer comprising: supplying a drying material for drying the wafer; and controlling a flow of the drying material to uniformly or substantially uniformly dry the wafer.
 42. The method of claim 41, wherein the flow of the drying material is controlled by providing a vent unit including at least one part having a plurality of vent holes, which determine a flow amount and flow pattern of the drying material through the vent unit.
 43. The method of claim 41, wherein the flow of the drying material is controlled so more drying material flows over a central region of the at least one part than an edge region of the at least one part.
 44. The method of claim 42, wherein the flow of the drying material is controlled by providing more of the plurality of vent holes in a central region of the at least one part than an edge region of the at least one part.
 45. The method of claim 42, wherein the flow of the drying material is controlled by providing larger vent holes in a central region of the at least one part than an edge region of the at least one part.
 46. The method of claim 42, wherein the flow of the drying material is controlled by providing more of the plurality of vent holes and larger vent holes in a central region of the at least one part than an edge region of the at least one part.
 47. The method of claim 42, wherein the flow of the drying material is controlled by providing at least two parts which interact to alter flow of the drying material through the plurality of vent holes.
 48. The method of claim 42, wherein the flow of the drying material is controlled by providing at least two parts and at least two auxiliary parts which interact to alter flow of the drying material through the plurality of vent holes.
 49. A drying apparatus comprising: a drying chamber for supplying a drying material for drying a wafer; and means for controlling a flow of the drying material to uniformly or substantially uniformly dry the wafer.
 50. The vent unit of claim 1, wherein the at least one part includes, a first exhausting unit having a plurality of first vent holes for ventilating the drying chamber, and a second exhausting unit having a plurality of second vent holes for ventilating a drying chamber, the first exhausting unit and the second exhausting unit being movable into a first position separating the drying chamber into two chambers.
 51. The vent unit of claim 50, wherein the first exhausting unit is movable through a first slit of the drying chamber, and the second exhausting unit is movable through a second slit of the drying chamber.
 52. The vent unit of claim 50, wherein each of the first and second exhausting units further include a horizontal ventilation outlet, and wherein when the first and second exhausting units are in a first position, the vent unit vents drying gas through the plurality of first vent holes and the plurality of second vent holes, and then the horizontal ventilation outlets. 